This invention relates to providing overvoltage protection for circuits and systems. For example, circuits in vehicle systems subject to overvoltage conditions resultant from load removal and the like or where integrated circuit microcontrollers are interfaced with motors via MOSFET(s) for motor position controllers such as may be employed in vehicle steering systems. Such systems may use control electronics to provide the interface between low voltage microcontrollers and the high voltage MOSFETs. The control electronics may also include motor control logic, a charge pump, MOSFET gate drives and overvoltage and overcurrent protection.
Unfortunately, many electronic systems include components that can be susceptible to voltage transients on their supply voltage. Such transients in certain circumstances may even destroy the components leading to early failure and excessive repairs. Therefore many circuits employ over voltage and/or over current protection schemes to prevent or avoid such transients or at least avoid the damage resulting from their occurrence.
A typical method to protect such electronics modules from transients and reverse voltage would be to use transient suppression devices to limit the voltage below the maximum input voltages for the devices. Unfortunately, if there were a great amount of energy in the transient pulse, the clamping devices would be very large and expensive. Moreover, reasonably sized varistors and the like would not be able to withstand the high peak currents seen during some transients. Transient voltage suppressors that can withstand the peak power are available but are large and expensive.
Therefore, it would be beneficial to provide a cost effective means of protecting circuits from over voltage transients.